Lower-thread mechanism for chain-stitch sewing-machines.



A. H. DE VOE.

LOWER THREAD MECHANISM FOR CHAIN STITCH SEWING MACHINES. APPLICATION FILED 05c. 18. 1914.

L257A 64. Patented Feb. 26, 1918 W11 2 SHEETS-SHEET l.

W/ T/VESSES: l/VVE/V TOR BY a, 4 QM $44M momm A H. DE VOEI LOWER THBEADIMECHANISM FOR CHAIN STITCH SEWING MACHINES.

APPLICATION FILED DEC. 18, I914. 1,257,464. Patented Feb. 2 1918.

2 SHEETS-SHEET z.

WITNESSES: INVENTOR BY 7-: K ATTORNEY ALBERT H. DE VOE, OF WESTFIELD, NEW JERSEY, ASSIGNOB TO THE SINGER MANUFAC- TURING COMPANY A CORPORATION OF NEW JERSEY.

LOWER-THREAD MECHANISM FOR CHAIN-STITCH SEWING-MACHINES.

Specification of Letters Patent.

Patented Feb. 26, 1918.

Application filed December 18, 1914. Serial No. 877,861.

To all whom it may concern:

Be it known that I, ALBERT H. DE Von, a citizen of the United States, residing at Westfield, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Lower-Thread Mechanism for Chain-Stitch Sewing-Machines, of which the following is a SPGClfiC-b tion, reference being bad therein to the ac companying drawings.

This invention has for its object to pro vide simple and effective means for impart ing to a looper from a single actuating element movements both endwise and crosswise of its blade in cooperation with a reciprocating needle for the production of stitches.

In the preferred embodiment of the invention, the looper is mounted for endwise and sidewise movements upon a carrier mounted to oscillate upon and slide endwise of a suitable support and having an operative connection with an actuating crank inclined to, and embraced within a plane parallel with, the axis of motion upon which it turns, said crank being adapted to impart to the looper both of its angularly related motions.

The invention also includes, in conjunction with said looper-actuating means, a lower thread take-up device comprising a rock-shaft carrying vibratory take-up arms and provided with a crank-arm having a toggle connection with an intermediate rockshaft deriving operative movements from a crank or eccentric upon the main-shaft. The operation of the take-up device is such that slack thread is rapidly given up to the loopers in their advance to extreme forward position and taken up with corresponding rapidity in the initial retractlon of the loopers, while the dwell and slight reverse move ment of the take-up arms in the retracted positions of the loopers serve to insure the proper control of the lower threads as the loopers are about to selze upper thread loops from the needles.

The invention will be understood by reference to the accompanying drawings, in which Figure 1 is a front elevation and Brig. 2 a plan of a portion of a two-line sewing machine embodying the present 1mprovements, and Fig. 3 is an end elevation of the same, partly in section. Fig. 4 1s an elevation, and Fig. 5 a plan of the loopers and their actuating means.

As represented in the drawings, the machine frame is provided with the bed 1 from which rise the bearing members 2 and 3, in which is journaled the rotary shaft 4 disposed lengthwise of the bed. The shaft is formed intermediate said bearings with the spaced and offset disks 5 and 6 which sustain between them the crank-pin 7 which is shown disposed at a slight inclination with the adjacent portions of the shaft 4 but axially within a plane arallel with and spaced from the axis of t e shaft.

The crank-pin 7 is embraced by a crankfollower in the form of a sleeve comprising the body portion 8 and cap 9 each provided with complement-a1 parts of the end flanges 10 and 11, the body portion 8 of the sleeve.

having depending therefrom the laterally inclined arm 12 formed at its lower end with a ball-socket closed by the cap 13.

The socket of the arm 12 embraces the head 14 of a bell-stud whose shank is secured by means of the set-screw 15 within a socket of a short lateral crank-arm 16 of the looper-carrier 17. The sleeve 8, 9, and the depending arm 12 will be seen to constitute a pitman connection between the crank-pin 7 and the looper-carrier 17. It is to be understood, however, that the pitman need not necessarily be directly connected to the looper-carrier or a part rigidly connected thereto, although a direct connection such as illustrated is preferred. The looper-carrier is formed with a transverse sleeve-like hub portion 18 which is slidingly mounted upon the eccentric bearing portion 19 of a pivotal pin formed at one end with the reduced portion 20 entering a suitable bearingaperture of the bed-plate bearing member 2 and at the opposite end an enlarged portion 21 similarly journaled within an aperture of the bearing member 3, the portion 22 beyond the enlarged portion 21 having fixed thereon the crank 23 adapted to be manually operated to shift the pivotal pin laterally, as described more particularly in my pending application Serial No. 793,535, filed October 6, 1913, which discloses a looper mechanism of which the present construction is a modification.

The looper-carrier has at its upper end a transverse head 24 having sockets to receive the depending pins 25 of the blocks 26 to which are secured by means of screws 27 the shanks 28 of the looper-blades 29. The looper-blades are provided adjacent their points with the thread-apertures 30 leading to which are the usual lateral grooves 31 for the thread passing through the guideeyes 32 at the heels of the loopers.

In the rotation of the shaft t, the crankpin 7 is carried in a path which is practically cylindrical and concentric with the axis of the shaft. This revolving movement of the crank-pin obviously acts through the arm 1:2 of the sleeve 8 to impart rocking movements to the looper-carrier 17, while the slight lateral inclination of the crankpin 7 causes the arm 12 to perform a slight vibratory movement which is transmitted through its ball-and-socket connection with the looper-carrier arm 16, thereby imparting to the latter its sidewise sliding movements. The rocking movements of the looper-carrier upon its pivotal support obviously communicates endwise or loop-seizing movements to the loopers, while the lateral sliding movements of the carrier impart to the loopers their usual sidewise movements.

Journaled in a forward extension of the bearing member 3 and in a post 33 at the I front of the bed 1 is the take-up rock-shaft 34 which is shown provided with the two thread-pins 35 each provided in its outer end with a thread-eye 36. The shaft 34. has secured thereon the collar 37 having the crank-arm 3S embraced by the forked lower extremity of the link 39 pivoted thereto by means of the pin e0, said link embracing within itsopposite forked end and pivotally secured by means of the pin 41 to the depending arm 42 of a collar i3 secured upon one end. of the intermediate rock-shaft 44..

The rock-shaft 4:4 is journaled within a bearing boss to of the post 33 and has fixed upon its opposite end the hub 46 of a crank arm e7 pivotally connected by means of the screw-stud 48 with the apertured boss 49 of the eccentric rod 50 provided with the strap 51 embracing the actuating eccentric fixed upon the main-shaft 4. The swinging movements of the crank-arm ".42 are such as to carry the link 39 into and out of alinement with itself, so as to produce a toggle movement for imparting a dwell and accelerated operative movements of the crankarm 38 from which the rock-shaft 34: and thread-arms 35 derive their operative movements.

Rising from the bed 1 is the thread-guide post 53 provided with the thread-eyes 5% through which one of the looper-threads is led to the outer thread-eye 36 of the nearer take-up arm 35 and thence to the corresponding looper 29, while the other is led through a second thread-eye 36 and thence to the eye of the seconcl take-up arm from which it is led to its respective looper.

' In the operation of the parts of the mechanism thus far described, in the retracted positions of the loopers and while the needle-thread loops are being set, the looperthread is slackened, but as the loopers begin their advance to seize new needle-thread loops, the slack is initially taken up by he take-up arms moving slightly backward as the toggle passes straightened position after which both loopers and take-up arms move forwardly, the take-up arms moving more rapidly as the loopers reach their advance positions, so as to give up a supply of tiie thread leading from the take-up eye to the eye of the loop-taker and backwardly to the work. As the loopers begin their receding movements, and rapidly give up the thread. of the loop thus formed, this thread is drawn up by the rapid retraction of the take-up arms so as to maintain the control at the thread into tlie initial retracted posi tion of the loopers.

The loopers cooperate with the usual eyepointed needles mounted in the plural needle-carrier 56 upon the reciprocating necdle-bar 57.

One of the chief advantages of the looger mechanism herein shown and described is the provision. for comparatively large wearing surfaces and few joints between the operative parts involving simplicity in construction, which insures durability and freedom from noise at high speeds. will be observed that in the present construction this mechanism involves only three pivotal. joints, comprising the sleeve of the crank member 12 embracing the actuating crank 7, the l')alland-socket connection between the same and the looper-carrier, and the journal of the looper-carrier upon the hearing portion 19 of the pivotal pin or support.

The feeding mechanism. is or may be constructed. in accordance with that of my pendin application Serial No. 813,8 1, filed Jannary 23, 191 1, and comprises the usual feeddog engaging the work through an aperture 59 in the throat-plate 60. Opposed to the feed-dog is the presser-foot 61 whose shank 62 is secured to the reduced lower extremity of the resser-bar 63.

Having thus set forth the nature of the invention, what I clain'i herein is 1. In a sewing machine, in combination, a looper, a carrier therefor, a support upon which. said loopencarrier is mounted for sidewise and endwise movement, an actuating shaft provided with a crank having its axis inclined thereto but movable in a substantially cylindrical path concentric therewith, and a pitman connection between said rl'ank and the looper-carrier from which the latter derives both of said movements.

2. In a sewing machine, in combination, an eye-pointed needle, a looper movable endwise to seize a needle-loop and sidewise to position a loop for subsequent entry by the needle, a carrier for said looper, a support upon which said carrier is mounted to slide and to oscillate, an actuating shaft provided with a crank having its axis inclined to, but movable in a substantially cylindrical path concentric with, the axis of said shaft, the axis of said crank being disposed in nonintersecting relation with the axis of said shaft, and a crank-follower embracing said crank and connected to the looper-carrier for imparting to the latter oscillatory and sliding movements, whereby the loo p-seizing movements of the said looper are caused to lie mainly in a direction at right angles to the direction of sliding movement of said looper-carrier on said support.

3. In a sewing machine, the combination with a reciprocating needle, a Work-support, a driving shaft, a thread-carrying looper and operative connections between said shaft and looper for imparting to said looper its loop-seizing and shedding movements, of a take-up comprising a rock-shaft, a crankarm and a thread-guiding arm carried by said rock-shaft, said thread-guiding arm being disposed adjacent the looper, an intermediate shaft carrying a crank-arm, operative connections between said intermediate shaft and said driving shaft independent of the connection between said driving shaft and looper, and a link connection between said crankarms adapted to move into and out of alinement with the crank-arm on said intermediate shaft.

4. In a sewing machine, the combination with a reciprocating needle, a work-support,

a driving shaft journaled below the work support, a thread-carrying looper mounted for needle-loop seizing movements transversely of said driving shaft, and operative connections between said shaft and looper,

of a take-up comprising a rock-shaft dis- 40 posed substantially parallel to said driving shaft, a crank-arm and a thread-guiding arm carried by said rock-shaft, said threadguiding arm being disposed adjacent the looper, an intermediate shaft carrying a 4 crank-arm, operative connections between said intermediate shaft and said driving shaft independent of the connections between said driving shaft and looper, and a link connection between said crank-arms adapted to move into and out of alinement with the crank-arm on said intermediate shaft.

In testimony whereof I have signed my name to this specification in the presence of Goples 0! this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

ashington, D. 0. 

